Apparatus for Reading Out X-ray Information Stored in Storage Phosphor Layer and Radiography Module

ABSTRACT

An apparatus ( 1 ) for reading out X-ray information of an X-ray image stored in a storage phosphor layer ( 4 ) is pivotable and includes acquiring unit ( 24 ) for acquiring an orientation of the apparatus ( 1 ). In this way, in a technically simple way, good image quality of an X-ray image read out can be guaranteed. Furthermore, the invention relates to a radiography module with this type of apparatus ( 1 ).

RELATED APPLICATIONS

This application claims priority to European Application No. EP05113053.2, filed on Dec. 29, 2005, which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

Apparatuses for reading out X-ray information stored in a storagephosphor layer are used in particular in the field of computerradiography (CR) for medical purposes. An image of an object, forexample a patient or a body part of the patient, is produced here bymeans of X-ray radiation, and this is stored in a storage phosphor layeras a latent image. This type of X-ray image therefore contains X-rayinformation about the object. In order to read out the X-ray informationstored in the storage phosphor layer, the storage phosphor layer isstimulated by means of an irradiation device. As a result of thisstimulation the storage phosphor layer emits light which has anintensity corresponding to the X-ray information stored in the storagephosphor layer. The light emitted from the storage phosphor layer iscollected by a detection device and is converted into electric signalswhich contain an image of the X-ray information. The electric signalsare further processed, and the X-ray information stored in the storagephosphor layer is then made visible. The X-ray information can be showndirectly on a monitor, for example, or by means of a printer usedspecially for X-ray images on a photographic X-ray film.

A read-out apparatus for reading out X-ray information is known which isin the form of an independent module which can be inserted or integratedinto different X-ray systems, such as e.g. an X-ray stand or X-raytable, for taking X-ray images. In order to read out the X-rayinformation, the read-out apparatus can remain in the X-ray system.Dependently upon the different embodiments of the X-ray systems used,the read-out apparatus can be inserted into the X-ray systems indifferent orientations or orientations. For this, the read-out apparatusis pivotable. For example, the read-out apparatus can be pivotable in anangle range of between 0° and 90° in relation to the horizontal. In thisway, it can be used very flexibly in a plurality of different X-raysystems. But also when reading out the X-ray information outside of anX-ray system, because of the possibility of pivoting, one is notrestricted to a single read-out position; one can in fact select this asappropriate depending upon the given circumstances. However, it has beenestablished that the quality of the X-ray images read out differsdependently upon the pivoting and in particular distortion can occur inthe X-ray image read out.

SUMMARY OF THE INVENTION

It is therefore the object of this invention to provide an apparatus forreading out X-ray information stored in a storage phosphor layer or aradiography module with which, in a technically simple way, good imagequality of the X-ray image read out can be guaranteed.

The apparatus according to the invention for reading out X-rayinformation stored in a storage phosphor layer includes an acquiringunit for acquiring an orientation of the apparatus. An apparatusaccording to the invention for reading out X-ray information isintegrated into the radiography module according to the invention.

The invention is based upon the knowledge that a pivotable read-outdevice is subjected to different loading due to the force of gravitydependently upon its orientation, i.e. its orientation or position.Because when reading out the X-ray information, very stringentrequirements are made of the read-out apparatus with regard tosynchronization and stringent requirements are made of the components ofthe read-out apparatus as regards the accuracy of their modes ofoperation and function, the force of gravity, which has varying degreesof effect upon the read-out apparatus and its components with differentorientations of the read-out apparatus, is of great significance.According to the invention it is possible, for example, to avoidartifacts in the X-ray image read out which occur dependently upon theorientation of the apparatus. These artifacts can occur, e.g. as aresult of bending of individual components of the read-out apparatus dueto their own weight. Furthermore, it is possible for distortions orartifacts to occur as a result of a change to the read-out speed withwhich the storage phosphor layer is read out. Dependently upon theorientation of the read-out apparatus e.g. slippage can occur duringread-out which can in particular be larger or smaller. This leads tochanges in the read-out speed. As a result of this invention, theapparatus is advantageously given the possibility of using informationregarding the orientation in order to avoid distortion and otherdamaging influences upon the quality of the X-ray image read out.Advantageously, for example, even before reading out the X-rayinformation a read-out speed to be expected during read-out can beestablished dependently upon the orientation acquired. Moreover, theinvention makes it possible to undertake two-dimensional calibration ofthe read-out apparatus because inhomogeneities in the storage phosphorlayer in X-ray images read out advantageously always occur at the samepoints.

In one advantageous embodiment of the invention, the acquiring unit isdesigned such that it acquires the direction of the acceleration due togravity. With this type of acquiring unit, the orientation of theapparatus can be established particularly easily and accurately.

Advantageously, the acquiring unit comprises at least one accelerationsensor. Numerous variations of this type of sensor are available so thata suitable and inexpensive sensor can easily be selected for thispurpose.

In a further advantageous embodiment, the acquiring unit comprises atleast one rotation sensor. With this type of rotation sensor theorientation can also be determined simply, reliably and inexpensively.This type of rotation sensor can in particular be disposed on an axis ofrotation of the apparatus. This leads to a particularly accurate result.

In one particularly preferred embodiment of the invention, a controlleris provided for processing the X-ray information read out from thestorage phosphor layer, and it is designed such that it processes theX-ray information read out dependently upon the acquiring of theorientation of the apparatus. In this way good quality of the X-rayimage can be achieved particularly efficiently in that the undesireddistortion which occurs during read-out is corrected by means of thecontroller when processing the X-ray information.

Preferably, the controller contains pre-specified details for processingthe X-ray information read out. It is designed such that it selects atleast some of the pre-specified details dependently upon the acquiringof the orientation of the apparatus and uses the details selected forprocessing the X-ray information. The details for processing the X-rayinformation read out can advantageously be contained in a table—aso-called look-up table—which can be incorporated into the controllerparticularly easily. The details for processing the X-ray informationread out can already be established for different orientations of theapparatus e.g. by means of tests before reading out the X-rayinformation.

In one preferred variation of the invention, an irradiation device forirradiating the storage phosphor layer with stimulation radiation and adetection device for collecting emission radiation which the storagephosphor layer emits as a result of irradiation by means of thestimulation radiation are provided. Furthermore, the irradiation deviceand the detection device are fixedly or rigidly associated with oneanother. In this way, the stimulation radiation can be directedparticularly accurately at the storage phosphor layer to be stimulated,and the emission radiation emitted by the storage phosphor layer as aresult of stimulation can be collected particularly accurately.Moreover, the apparatus can advantageously have an actuation device forproducing a relative movement between the storage phosphor layer on theone hand and the stimulation device and the detection device on theother hand. Particularly advantageously, the read-out i.e. thestimulation of the storage phosphor layer and the collection of theemission radiation takes place line by line.

In a particularly preferred further development of the invention furthera controller is provided for controlling the apparatus. The furthercontroller is designed such that it controls the read-out of the X-rayinformation dependently upon the acquiring of the orientation of theapparatus. In this case, the read-out itself is implemented in anappropriate way such that undesired distortion is avoided early on, whencollecting the X-ray information. The further controller can control oneor more components of the apparatus as appropriate dependently upon theorientation acquired.

It is particularly preferred if the further controller is designed suchthat it controls the irradiation device dependently upon the acquiringof the orientation of the apparatus. Advantageously, different read-outdepths in the storage phosphor layer can be avoided here. These occurwith different read-out speeds as a result of changes to the stimulationradiation applied to the storage phosphor layer. With a slow read-outspeed, the quantity of the stimulation radiation applied to the storagephosphor layer is greater, by means of which the quantity of emissionradiation emitted also correspondingly changes. Therefore, with a slowread-out speed, the intensity of the X-ray information read out isgenerally different than with a fast read-out speed.

Advantageously, the further controller is designed such that it controlsthe detection device dependently upon the acquiring of the orientationof the apparatus. Here, the time over which the detection device absorbsemitted emission radiation is correspondingly adjusted dependent uponthe orientation of the apparatus.

Preferably, the further controller is designed such that it controls thespeed of the relative movement dependently upon the acquiring of theorientation of the apparatus. By acquiring the orientation of theapparatus it is possible to establish what effect the force of gravityis having upon the apparatus, in particular its actuation device. Thespeed itself can therefore be controlled in a technically simple manner.One of the basic causes for the occurrence of distortion can in this waybe eliminated from the outset.

In a particularly advantageous embodiment of the invention, the furthercontroller contains pre-specified details for controlling the apparatus.it is designed such that it selects some of the pre-specified detailsdependently upon the acquiring of the orientation of the apparatus, anduses the details selected in order to control the apparatus. The detailsfor controlling the apparatus can advantageously be contained in atable—a so-called look-up table—which can be incorporated particularlyeasily into the further controller. The details for controlling theapparatus can already be established for different orientations of theapparatus, e.g. by means of tests, before reading out the X-rayinformation. The details advantageously include control parameters forthe further controller which uses the latter for controlling theirradiation device, the detection device and/or for controlling thespeed of the relative movement.

Preferably, a further acquiring unit is provided for acquiring a speedof the relative movement. In this way, the current speed of the relativemovement can be determined. If, for example, this deviates from adesired speed, the apparatus, in particular the controller, can take thedeviation into account when processing the X-ray information read out.Alternatively, or in addition, the further controller can also use thedeviation when controlling the apparatus. In this way, furtherimprovement in the quality of the X-ray image can be achieved. With anexpected constant speed during the read-out of the X-ray information ofan X-ray image it is sufficient to determine the speed a single time.But it is also possible to acquire the speed several times. In this way,any deviation in the speed can be acquired with greater accuracy and itcan be correspondingly corrected. This can be particularly advantageousif slippage occurring during read-out changes during the read-out. Thesechanges can then be acquired and appropriately corrected.

It is particularly preferred if the further acquiring unit is designedsuch that it acquires at least an average speed of the relativemovement. This average speed occurs during the read-out of the X-rayinformation between at least two relative positions between the storagephosphor layer on the one hand and the stimulation and detection deviceon the other hand. This type of determination of the average speed isparticularly easy to convert.

Preferably, the further acquiring unit has at least two sensors whichare allocated to the at least two relative positions. The at least twosensors serve to determine a time required by the relative movement whenreading out the X-ray information between reaching the at least twopositions. The sensors can in particular be photo sensors. This isparticularly cost-effective and easy to implement.

Advantageously, the apparatus is designed such that it allocates theorientation of the apparatus acquired by the acquiring unit and thespeed acquired by the further acquiring unit to one another, and addsthis allocation to the pre-specified details for processing the X-rayinformation. In this way, a self-learning apparatus can be producedwhich can refine the allocation of the orientation of the apparatus tothe read-out speed achieved with this orientation with every X-ray imageread out, and in this way continue to improve the correction by thesecontroller. This advantageously benefits the read-out of subsequentX-ray images.

It is particularly advantageous if the apparatus is designed such thatit allocates the orientation of the apparatus acquired by the acquiringunit and the speed acquired by the further acquiring unit to one anotherand adds this allocation to the pre-specified details for controllingthe apparatus. In this way a self-learning apparatus can be producedwhich can refine the allocation of the orientation of the apparatus tothe read-out speed achieved with this orientation with every X-ray imageread out, and in this way continue to improve the correction by thefurther controller.

The above and other features of the invention including various noveldetails of construction and combinations of parts, and other advantages,will now be more particularly described with reference to theaccompanying drawings and pointed out in the claims. It will beunderstood that the particular method and device embodying the inventionare shown by way of illustration and not as a limitation of theinvention. The principles and features of this invention may be employedin various and numerous embodiments without departing from the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, reference characters refer to the sameparts throughout the different views. The drawings are not necessarilyto scale; emphasis has instead been placed upon illustrating theprinciples of the invention. Of the drawings:

FIG. 1 is a schematic, perspective illustration of an example of anembodiment of an apparatus according to the invention for reading outX-ray information stored in a storage phosphor layer, the apparatusbeing in the form of a radiography module;

FIG. 2 is a further schematic illustration of a structure of theradiography module according to FIG. 1;

FIG. 3 is a schematic illustration of an example of an application ofthe radiography module according to FIG. 1 fitted in an X-ray system;

FIG. 4 is a schematic illustration of a top view of the radiographymodule according to FIG. 1;

FIG. 5 is a sequence diagram with a first example of a sequenceaccording to the invention in the radiography module according to FIG.1;

FIG. 6 is a sequence diagram with a second example of a sequenceaccording to the invention in the radiography module according to FIG.1;

FIG. 7 is a sequence diagram with a third example of a sequenceaccording to the invention in the radiography module according to FIG.1;

FIG. 8 is a sequence diagram with a fourth example of a sequenceaccording to the invention in the radiography module according to FIG.1;

FIG. 9 is a sequence diagram with a fifth example of a sequenceaccording to the invention in the radiography module according to FIG.1; and

FIG. 10 is a sequence diagram with a sixth example of a sequenceaccording to the invention in the radiography module according to FIG.1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a schematic, perspective illustration of an example of anembodiment of a read-out apparatus according to the invention forreading out X-ray information stored in a storage phosphor layer. Theread-out apparatus here is in the form of a radiography module 1. Theradiography module 1 can be inserted or integrated into different X-raysystems, such as e.g. an X-ray stand or an X-ray table for taking X-rayimages. For this, the radiography module 1 is pivotable. In order toread out the X-ray image stored in the storage phosphor layer theradiography module 1 can remain in the X-ray system and does not have tobe—as with a conventional X-ray cassette—removed from the X-ray systemand conveyed to a separate read-out station.

The radiography module 1 comprises a housing 2 in which a storagephosphor plate 3 is disposed. The storage phosphor plate 3 has a storagephosphor layer 4 and a support layer to which the storage phosphor layer4 is applied (FIG. 2). Here, the storage phosphor layer 4 is the toplayer of the storage phosphor plate 3. The storage phosphor plate 3 isdisposed securely in the housing 2 of the radiography module 1, i.e. thestorage phosphor plate 3 is connected securely to the housing 2 by meansof suitable connection elements. The connection to the housing 2 can berigid or swinging, e.g. by means of appropriate suspension elements soas to attenuate any external impacts to the housing 2 and transfer ofthe latter to the storage phosphor plate 3.

Furthermore, the radiography module 1 includes a reading head 5 forreading out the X-ray information from the storage phosphor layer 4. Thereading head 5 is mounted movably in the housing 2. For this, disposedin the region of the two long sides of the storage phosphor plate 3 areguides 6 and 7 which provide the reading head 5 with bearings,preferably in the form of air bearings, and guidance. In order to readout the X-ray information, the scanning head 5 is actuated by anappropriate actuator 8, e.g. a linear motor or a step motor with afriction wheel gear and cable drive, and moved over the storage phosphorplate 3 in conveyance direction T. A relative movement for read-outtherefore takes place between the storage phosphor layer 4 and thereading head 5. Actuation of the reading head 5, and so the relativemovement between the storage phosphor layer 4 and the reading head 5,takes place continuously with a very precise linear and constant speed.In this example of an embodiment the reading head 5 can be moved overthe storage phosphor layer 4, whereas the storage phosphor layer 4 issecurely disposed in the housing 2. However, it is also possible todispose the reading head 5 securely in the housing and to move thestorage phosphor plate 3 past the reading head 5.

In addition to the reading head 5, a deletion lamp 9 is provided whichcan also be actuated by the actuator 8 and moved over the storagephosphor layer 4. The deletion lamp 9 serves to delete any remaininginformation in the storage phosphor layer 4 which may still be presentafter read-out before a subsequent X-ray is taken.

Furthermore, a control device 10 is provided which controls the read-outand deletion process as well as any signal processing processes. Variousinterfaces 11 are provided on the control device 10 which are requiredfor transferring energy, possibly air, control signals and/or imagesignals, to and from the radiography module 1.

FIG. 2 shows a further schematic illustration of a structure of theradiography module 1 according to FIG. 1. The radiography module 1 isshown in a side view here. The storage phosphor plate 3 is shown whichhas a support layer 12 and the storage phosphor layer 4. The storagephosphor layer 4 is preferably made up of a plurality of phosphorparticles which serve to store the X-ray information. The support layer12 can be a laminate which is made up of various layers and materials.The support layer 12 is a transparent support layer here which ispartially permeable to radiation.

The reading head 5 includes an irradiation device 13 which serves toirradiate the storage phosphor layer 4 with stimulation radiation 14. Alaser diode line is used here as the irradiation device 13, and thiscontains a plurality of laser diodes disposed next to one another. Withthis laser diode line a line of the storage phosphor layer 4 is at thesame time irradiated and stimulated. However, it is also possible to usean irradiation device 13 of a different form.

As a result of the stimulation of the storage phosphor layer 4 by meansof the stimulation radiation 14, the storage phosphor layer 4 emitsemission radiation 15 the intensity of which is dependent upon the X-rayinformation stored in the storage phosphor layer 4. In order to collectthe emission radiation emitted the reading head 5 includes a detectiondevice 16. Here, the detection device 16 has a line detector which caninclude a so-called “charge-coupled device” (CCD) line. The CCD line hasa plurality of photodetectors disposed parallel and in a line next toone another. By means of the detection device 16 a photoelectricconversion of the emission radiation 15 received can be implemented. Thedetection device 16 is read out at pre-specified intervals of time.Alternatively, the detection device 16 can have, instead of the CCDline, a light conductor, for example, to which a photomultiplier isattached. There is a secure connection between the irradiation device 13and the detection device 16 so that the image of the X-ray informationstored in the storage phosphor layer 4, i.e. the stimulation of thestorage phosphor layer 4 and the receipt of the radiation 15 emitted asa result of stimulation, are matched precisely to one another, andaccurate allocation is always guaranteed, even during the actualread-out process.

In this example of an embodiment, the irradiation device 13 is disposedbeneath and the detection device 16 above the storage phosphor plate 3.The irradiation device 13 is directly adjacent to the support layer 12and the detection device 16 to the storage phosphor layer 4. Thestimulation radiation 14 can thus penetrate into the transparent supportlayer 12 and pass from underneath into the storage phosphor layer 4.

The control device 10 includes first controller 17 for controlling theradiography module 1 and its components. The first controller 17therefore controls in particular the functions of the irradiation device13 and the detection device 16 and of the actuator 8 (see FIG. 1). Thefirst controller 17 is connected to these components of the radiographymodule 1. Furthermore, the control device 10 has second controller 18for processing the X-ray information read out from the storage phosphorlayer 2. The second controller 18 is connected in particular to thedetector 16 in order to process the electric signals produced by thelatter which contain an image of the X-ray information stored in thestorage phosphor layer 4. The two controllers 17 and 18 can also berealized by means of a single controller.

In order to read out the X-ray information, the reading head 5, i.e.both the irradiation device 13 and the detection device 16, are moved bymeans of the actuator 8 with a conveyance speed along the storagephosphor plate 3 in conveyance direction T. The size of the pixels inthe X-ray image read out, and so the resolution of the latter, asobserved in conveyance direction T, is dependent, among other things,upon this conveyance speed and the pre-specified interval of time forthe read-out of the detection device 16. The radiography module 1according to the invention includes three sensors with which theconveyance speed can be reviewed. A first sensor 19, 19′ is, as observedin conveyance direction T, disposed at the start of the storage phosphorplate 3, a second sensor 20, 20′ at its end, and a third sensor 21, 21′in the first third of the storage phosphor plate 3. Alternatively, oneor more of these sensors 19, 19′ and 20, 20′ and 21, 21′can also bedisposed in front of the storage phosphor plate 3. Moreover, it ispossible to provide further or also fewer sensors. The sensors 19, 19′,20, 20′, 21, 21′ here are photo sensors which detect the reading head 5passing through them. It is also possible, however, to use other typesof sensor. By means of the two sensors 19, 19′ and 20, 20′ a time at thestart and a time at the end of the read-out process can be established.The sensor 21, 21′ establishes a time still relatively at the start ofthe read-out process, however after a sufficient distance has beencovered, so as to guarantee that a measurement result for a relevantdistance is determined. By means of the sensors 19, 19′, 20, 20′, 21,21′ the time is measured which the reading head 5 requires in order tocover the distance between the sensors 19, 19′, 20, 20′, 21, 21′. Thisgives an average conveyance speed for the reading head 5 because thedistances are known.

The sensors 19, 19′, 20, 20′, 21, 21′ are connected to both controller17, 18 in order to relay the reading head 5 passing through them for useby the controller 17, 18. The controller 17, 18 can establish adeviation of the average conveyance speed measured from a pre-specifiedconveyance speed. Thereupon, they can trigger the appropriatecounter-measures.

The first controller 17 for controlling the radiography module 1 canadvantageously undertake correspondingly appropriate control ofcomponents of the radiography module 1 directly after the third sensor21, 21′ has been passed through by the reading head 5 with a speed to becorrected. Because the third sensor 21, 21′ is already disposed here inthe first third of the distance to be covered in order to read out theX-ray information, the first controller 17 can, if appropriate, alreadyundertake appropriate control of the components during the furtherread-out of the current X-ray image. The actuator 8 can be triggered todrive the reading head 5 faster or slower dependently upon thecorrection to be made. In addition, or alternatively, the firstcontroller 17 can be designed such that it controls the irradiationdevice 13 such that it appropriately changes the radiation intensity ofthe stimulation radiation 14 or the duration of the irradiation of thestimulation radiation into a line of the storage phosphor layer. If theconveyance speed is too high, the radiation intensity of the stimulationradiation can advantageously be increased, and if the conveyance speedis too slow, it can be reduced so as to obtain the most constantpossible radiation quantities of stimulation radiation when stimulatingthe lines of the storage phosphor layer 4. Furthermore, in addition oralternatively, the first controller 17 can be designed such that theycontrol the detection device 16 such that the time taken to collectemission radiation for each line of the storage phosphor layer 4 ischanged. With excessively high conveyance speed the time canadvantageously be shortened, and with excessively slow conveyance speedit can be increased so as to obtain the most constant pixel size, and soresolution, in the X-ray image possible, observed in conveyancedirection T. The distances which are covered by the reading head 5 forthe read-out of the individual lines of the storage phosphor layer 4 arethen constant.

The second controller 18 for processing the X-ray information read outis advantageously designed such that it processes the X-ray informationread out dependently upon the conveyance speed acquired. The secondcontroller 18 here contains pre-specified details for processing theX-ray information read out. These details include guidelines as to howthe X-ray information read out is to be corrected. The details arestored in a storage unit 22 of the second controller 18, especially asso-called look-up tables. They were advantageously determined bypreliminary tests and give typical correction possibilities whichcorrespond in particular to experienced values. The second controller 18is designed such that it selects at least some of the pre-specifieddetails dependently upon the conveyance speed acquired and uses thedetails selected in order to process the X-ray information. The secondcontroller 18 establishes, as viewed in the direction of the relativemovement, the pixel size of the X-ray information read out and/or anintensity of the X-ray information read out dependently upon theconveyance speed acquired. It can therefore be guaranteed that theintensities of X-ray images read out and processed are the same and thattheir resolutions, in particular as observed in conveyance direction T,are constant.

As already described above, the radiography module 1 is pivotable. Thisis indicated in FIG. 2 by an arcuate double arrow S. In order to pivot,the radiography module 1 can have an axis of rotation around which itcan pivot. The radiography module 1 can be used in differentorientations i.e. orientations or positions. The orientation of theradiography module 1 is given, for example, by the design of an imagetaking device for the radiography module 1 in an X-ray system, e.g. anX-ray table, in which the radiography module 1 is inserted. This imagetaking device can be inclined in relation to a horizontal. FIG. 3 showsan example of an X-ray system 23 into which the radiography module 1 hasbeen inserted. The radiography module 1 has an inclination N in relationto a horizontal H in the X-ray system 23. Due to the inclination N ofthe radiography module 1, the storage phosphor plate 3 and the readinghead 5 also have this type of inclination N. This means that when thereading head 5 is actuated by the inclined, pivoted orientation of theradiography module 1, a force of gravity g acts upon the actuation, i.e.the movement in conveyance direction T, of the reading head 5. The forceof gravity g results from the acceleration due to gravity. Becauseduring movement a very high degree of synchronization is required by thereading head 5, this effect of the force of gravity g can bedisadvantageous for the read-out of the stored X-ray information andcause distortion in the X-ray image read out. When actuating the readinghead 5 by means of the actuator 8, under certain circumstances slippagecan occur such that artifacts are produced. Dependently upon the degreeof inclination N, the effect of the force of gravity g can vary instrength.

According to the invention the radiography module 1 includes acquiringunit 24 for acquiring its orientation. Of particular interest here isits orientation in relation to the horizontal. The acquiring unit canfor example be an acceleration sensor which acquires the direction ofthe acceleration due to gravity. In this way it can be determined inwhich direction the load is applied to the reading head 5 by the forceof gravity. The acquiring unit 2 is connected to the control device 10,and in particular to the two controllers 17, 18 (FIG. 2). Theorientation established can therefore be relayed to the controller 17,18 for further processing.

The first controller 17 is designed such that it controls the read-outof the X-ray information dependently upon the orientation of the X-raymodule 1 acquired. For this, the first controller 17 controls one ormore of the components of the radiography module 1, in particular theirradiation device 13, the detection device 16 and/or the actuator 8 asappropriate. This control is implemented in the appropriate manner, asdescribed above in connection with the change to the conveyance speed.Even stimulation of the lines of the storage phosphor layer 4,appropriate collecting of the emission radiation 15 and/or a constantconveyance speed should thus advantageously be guaranteed. The firstcontroller 17 includes pre-specified details for controlling theapparatus. These details include guidelines as to how the respectivecomponents of the radiography module 1 are to be appropriatelycorrected. The details are stored in a storage unit 25 of the firstcontroller 17 as so-called look-up tables. They were advantageouslydetermined by preliminary tests, and give typical correctionpossibilities which correspond in particular to experienced values. Thedetails correspond to calibration characteristic lines or calibrationimages. The first controller 17 is designed such that it selects some ofthe pre-specified details dependently upon the orientation of theradiography module 1 acquired and use the details selected in order tocontrol it.

The second controller 18 is designed such that it processes the X-rayinformation read out dependently upon the acquiring of the orientationof the X-ray module 1. Further pre-specified details for processing theX-ray information read out are contained in the storage unit 22 here.The pre-specified details were also established by preliminary tests andgive possibilities for how the X-ray information read out can becorrected dependently upon the orientation, i.e. in particular the levelof inclination N. The further details are also stored in the form ofso-called look-up tables. The second controller 18 is designed such thatit selects at least some of the pre-specified details dependently uponthe orientation of the radiography module 1 acquired and use theselected details for processing the X-ray information. As describedabove in connection with the change in conveyance speed, the intensityand/or the resolution of the X-ray images should be adjusted here asappropriate.

In this example of an embodiment, the radiography module 1 isself-learning. The radiography module 1 is designed such that itallocates the orientation acquired by the acquiring unit 24 and theconveyance speed of the reading head 5 acquired by the sensors 19, 19′,20, 20′, 21, 21′ when this acquired orientation is available, to oneanother. This allocation is then added to the pre-specified detailsstored in the storage unit 22 for processing the X-ray information andto the pre-specified details stored in the storage unit 25 forcontrolling the radiography module 1. In this way, these details cancontinue to be refined and improved. With increasing use of theradiography module 1, its correction from distortion occurring as aresult of pivoting away from the horizontal is constantly improved. Thiscan be used for subsequent X-ray images.

FIG. 4 shows a schematic illustration of a top view of the radiographymodule 1. This illustration makes it clear that the radiography module 1can have an axis of rotation 26 around which it can be pivoted. The axisof rotation 26 is indicated in FIG. 4 on the left-hand edge of theradiography module 1. In order to acquire the orientation of theradiography module 1 in the pivoted state, the acquiring unit 24 canhave a rotation sensor. The rotation sensor is advantageously positionedon the axis of rotation 26 and advantageously acquires the orientationof the radiography module 1 in relation to its axis of rotation 26.

FIG. 5 shows a sequence diagram of a sequence according to the inventionfor adapting the conveyance speed of the reading head 5 in theradiography module 1. In step 30, the orientation of the radiographymodule 1 is determined. Then, by means of the orientation thusdetermined, in step 31 parameters are calculated which serve to controlthe actuation 8. By means of these control parameters the X-rayinformation is then read out from the storage phosphor layer 4 in step32, and at the same time the conveyance speed of the reading head 5 ismeasured. The X-ray information read out is relayed to the secondcontroller 18 and thereupon, in step 33, the X-ray information isprocessed and corrected. In a subsequent step 34, the data of the X-rayimage are further processed, stored, and the X-ray image is displayed ona monitor or an X-ray film is exposed.

FIG. 6 shows a sequence diagram of a sequence according to the inventionfor controlling the irradiation device 13 and/or the detection device 16in order to correct a change to the conveyance speed. The sequencediagram according to FIG. 6 largely corresponds to that according toFIG. 5. However, after step 30, in step 35, the intensity of thestimulation radiation 14 required to stimulate the storage phosphorlayer 4 and/or the read-out time for the read-out of the detectiondevice 16 is established dependent upon the orientation established.These details are then correspondingly used in step 32 for reading outthe X-ray information.

FIG. 7 shows a sequence diagram of a sequence according to the inventionfor correcting undesired distortions in the X-ray information read outby means of the second controller 18. In step 30 the orientation of theradiography module 1 is first of all acquired once again. Theorientation acquired is communicated to the second controller 18, andthe latter thereupon calculates appropriate correction parameters instep 36. These correction parameters are used in step 37 when processingthe X-ray information read out in step 32.

FIG. 8 shows a sequence diagram of a sequence according to the inventionof an adaptation of the conveyance speed of the reading head 5 in theradiography module 1 by means of correction parameters previouslyestablished with previous X-ray images. FIG. 8 largely corresponds toFIG. 5. However, an additional step 38 is included with which theorientation acquired in step 30 and the conveyance speed measured instep 32 are allocated. This allocation is stored. The parameters forcontrolling the actuator 8 in step 31 are calculated here by means ofthe stored allocations of previous read-out processes.

The same applies for FIG. 9 which shows a sequence diagram of a sequenceaccording to the invention for controlling the irradiation device 13and/or the detection device 16 for correcting a change to the conveyancespeed. FIG. 9 largely corresponds to FIG. 6, the additional step 38 alsobeing included here. The intensity of stimulation radiation 14 requiredto stimulate the storage phosphor layer 4 and/or the read-out time forthe read-out of the detection device 16 for the current X-ray image areadditionally established in step 35 dependently upon the allocation ofthe orientations acquired in step 30 and the conveyance speeds measuredin step 32.

The same also applies for FIG. 10 which gives a sequence diagram of asequence according to the invention for correcting undesired distortionsin the X-ray information read out by means of the second controller 18.FIG. 10 largely corresponds to FIG. 7, the additional step 38 also beingincluded here. The orientation for the current X-ray image acquired instep 30 and the allocation of orientations acquired in step 30 andconveyance speeds of previous X-ray images measured in step 32 are usedby the second controller 18 for calculating appropriate correctionparameters.

This is a list of references: 1 radiography module; 2 housing; 3 storagephosphor plate; 4 storage phosphor layer; 5 reading head; 6 guide; 7guide; 8 actuator; 9 deletion lamp; 10 control device; 11 interfaces; 12support layer; 13 irradiation device; 14 stimulation radiation; 15emission radiation; 16 detection device; 17 first controller; 18 secondcontroller; 19, 19′ sensor; 20, 20′ sensor; 21, 21′ sensor; 22 storageunit; 23 X-ray system; 24 acquiring unit; 25 storage unit; 26 axis ofrotation; 30 to 38 sequence steps; T conveyance direction; H horizontal;N inclination; g force of gravity; and S pivot direction.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. An apparatus for reading out X-ray information of an X-ray image stored in a storage phosphor layer, the apparatus being pivotable, the apparatus comprising: an acquiring unit for acquiring an orientation of the apparatus.
 2. The apparatus according to claim 1, wherein the acquiring unit determines a direction of acceleration due to gravity relative to the apparatus.
 3. The apparatus according to claim 1, wherein the acquiring unit comprises at least one acceleration sensor.
 4. The apparatus according to claim 1, wherein the acquiring unit comprises at least one rotation sensor.
 5. The apparatus according to claim 4, wherein the at least one rotation sensor is disposed on an axis of rotation of the apparatus.
 6. The apparatus according to claim 1, wherein the controller processes the X-ray information read out from the storage phosphor layer and processes the X-ray information read out depending upon the orientation of the apparatus.
 7. The apparatus according to claim 6, wherein the controller has specified details for processing the X-ray information read out and is designed such that it selects at least some of the pre-specified details depending upon the orientation of the apparatus and uses the details selected for processing the X-ray information.
 8. The apparatus according to claim 1, further comprising an irradiation device for irradiating the storage phosphor layer with stimulation radiation and a detection device for collecting emission radiation which the storage phosphor layer emits as a result of irradiation by means of the stimulation radiation, the irradiation device and the detection device being rigidly associated with one another.
 9. The apparatus according to claim 1, further comprising a controller for controlling the read-out of the X-ray information depending upon the orientation of the apparatus.
 10. The apparatus according to claim 9, wherein the controller controls the irradiation device depending upon the orientation of the apparatus.
 11. The apparatus according to claim 8, wherein the controller controls the detection device depending upon the orientation of the apparatus.
 12. The apparatus according to claim 9, further comprising an actuation device for producing a relative movement between the storage phosphor layer on the one hand and the stimulation device and the detection device on the other hand.
 13. The apparatus according to claim 12, wherein the controller controls the speed of the relative movement depending upon the orientation of the apparatus.
 14. The apparatus according to claim 9, wherein the controller stores pre-specified details for controlling the apparatus and selects between the pre-specified details depending upon the orientation of the apparatus and uses the details selected for controlling the apparatus.
 15. The apparatus according to claim 12, wherein the acquiring unit acquires a speed of the relative movement.
 16. The apparatus according to claim 15, wherein the acquiring unit determines at least an average speed of the relative movement, this average speed occurring during the read-out of the X-ray information between at least two relative positions between the storage phosphor layer on the one hand and the stimulation device and detection device on the other hand.
 17. The apparatus according to claim 16, further comprising at least two sensors which are allocated to the at least two relative positions and serve to determine a time required by relative movement when reading out the X-ray information between the at least two positions.
 18. The apparatus according to claim 15, wherein the controller processes the X-ray information read out from the storage phosphor layer and processes the X-ray information read out depending upon the orientation of the apparatus and has specified details for processing the X-ray information read out and is designed such that it selects at least some of the pre-specified details depending upon the orientation of the apparatus and uses the details selected for processing the X-ray information, and compares the orientation of the apparatus and the speed to one another, modifies pre-specified details for processing the X-ray information.
 19. The apparatus according to claim 15, wherein the controller stores pre-specified details for controlling the apparatus and selects between the pre-specified details depending upon the orientation of the apparatus and uses the details selected for controlling the apparatus and wherein the controller is designed such that it compares the orientation of the apparatus acquired by the acquiring unit and the speed to one another and uses this comparison with to the pre-specified details for controlling the apparatus.
 20. A radiography X-ray cassette, comprising a housing; and an apparatus for reading out X-ray information of an X-ray image stored in a storage phosphor layer in the housing, the apparatus including an acquiring unit for acquiring an orientation of the housing.
 21. The cassette according to claim 20, wherein the acquiring unit determines a direction of acceleration due to gravity relative to the apparatus.
 22. The cassette according to claim 20, wherein the acquiring unit comprises at least one acceleration sensor.
 23. The cassette according to claim 20, wherein the acquiring unit comprises at least one rotation sensor.
 24. The cassette according to claim 23, wherein the at least one rotation sensor is disposed on an axis of rotation of the apparatus.
 25. The cassette according to claim 1, further comprising a controller that processes the X-ray information read out from the storage phosphor layer and processes the X-ray information read out depending upon the orientation of the apparatus.
 26. An method for reading out X-ray information of an X-ray image stored in a storage phosphor layer with a read out apparatus, the method comprising: acquiring an orientation of the read out apparatus; controlling a processing of the X-ray image in response to the orientation.
 27. The method according to claim 26, wherein the step of acquiring the orientation comprises determining a direction of acceleration due to gravity relative to the apparatus.
 28. The method according to claim 26, wherein the step of acquiring the orientation comprises measuring rotation of the apparatus.
 29. The method according to claim 26, wherein the step of controlling the processing comprises controlling an irradiation device for irradiating the storage phosphor layer with stimulation radiation and a detection device for collecting emission radiation which the storage phosphor layer emits as a result of irradiation by means of the stimulation radiation in response to the orientation. 